Device for joint detection of cdma codes for multipath downlink
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Accused Products
Abstract
A conjoint detection device for UMTS/TDD mobile radio telephone terminal receiver processes a received signal having symbols coded in accordance with K CDMA codes and having passed through a propagation channel with Lt multiple paths. The device has two channels each imposing Lt/2 respective delays and each having K filtering branches. Each filtering branch correlates Lt/2 delayed sample sequences to a respective code and to Lt/2 estimated path coefficients in order to sum Lt/2 coefficients correlated in this way sampled at the symbol period. 2K equalization filters then equalize linearly the 2K correlated signals, depending on an associated code, before they are summed at the output of the two channels. Thanks to the division into two channels, there are sufficient degrees of freedom to cancel the interference out exactly for a finite depth of the 2K equalization filters greater than twice the duration of the propagation channel.
15 Citations
17 Claims
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1-4. -4. (canceled)
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5. A conjoint detection device for a received signal supporting symbols each conjointly coded by K codes and sampled at one chip period at most, said received signal being arranged to have passed through a propagation channel with Lt multiple paths, said device comprising:
two parallel channels each arranged for grouping;
Lt/2 respective parallel delay means for delaying samples of said received signal with respective estimated delays caused by said paths into Lt/2 delayed sample sequences, K filtering means respectively associated with said K codes, each filtering means being arranged for correlating said Lt/2 delayed sample sequences to the respective code and to Lt/2 estimated path coefficients into Lt/2 correlated signals arranged to be delivered at said symbol period and summing said Lt/2 correlated signals into one of K correlated signals, and K equalization means respectively for linearly equalizing said K correlated signals depending on one of said K codes assigned to said device into K equalized signals, and means for summing all said K equalized signals at said symbol period arranged to be delivered conjointly by all said K equalization means in said two parallel channels. - View Dependent Claims (6, 7, 8, 9)
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10. A conjoint detection device for a received signal supporting symbols each conjointly coded by K codes and sampled at one chip period at most, said received signal being arranged to have passed through a propagation channel with Lt multiple paths, said device comprising:
two parallel channels each arranged for grouping;
Lt/2 respective parallel delays for delaying samples of said received signal with respective estimated delays caused by said paths into Lt/2 delayed sample sequences, K filters respectively associated with said K codes, each filter being arranged for correlating said Lt/2 delayed sample sequences to the respective code and to Lt/2 estimated path coefficients into Lt/2 correlated signals, the K filters being arranged to deliver the Lt/2 correlated signals at said symbol period and sum said Lt/2 correlated signals into one of K correlated signals, K equalizers respectively for linearly equalizing said K correlated signals depending on one of said K codes assigned to said device into K equalized signals, and a summer for summing all said K equalized signals at said symbol period arranged to be delivered conjointly by all said K equalizers in said two parallel channels. - View Dependent Claims (11, 12, 13, 14)
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15. A conjoint detection method responsive to a received signal supporting symbols each conjointly coded by K codes and sampled at one chip period at most, said received signal having passed through a propagation channel with Lt multiple paths, said method comprising:
supplying the received signal to two parallel channels, each channel performing the following steps;
delaying samples of said received signal with respective estimated delays caused by said paths into Lt/2 delayed sample sequences;
correlating said Lt/2 delayed sample sequences to the respective code and to Lt/2 estimated path coefficients into Lt/2 correlated signals delivered at said symbol period and summing said Lt/2 correlated signals into one of K correlated signals;
linearly equalizing said K correlated signals depending on one of said K codes into K equalized signals; and
conjointly summing all said K equalized signals at said symbol period. - View Dependent Claims (16, 17)
Specification